### What this PR does / why we need it? Fix `ValueError: Unrecognized distributed executor backend tp. Supported values are 'ray', 'mp' 'uni', 'external_launcher' or custom ExecutorBase subclass.` ### Does this PR introduce _any_ user-facing change? No ### How was this patch tested? Test on my local node Signed-off-by: Yikun Jiang <yikunkero@gmail.com>